I'm going through my stash of power tubes and have some to sell: starting with the best:  
SED 6L6GC Winged 'C' - low low hours/matched quad $400 new/selling for $250.
Mullard EL-34 RE-Issue matched quad: $100 new/now $50.
Gold Lion KT-77 Matched Quad: $200 new/now $75. (I'm less certain about the hours on these as they came with the amp, but pretty sure these have a lot of life left.)